The present invention relates to construction panels used in roofing applications, and more specifically to relatively thin roofing panels made of homogeneous gypsum fiber panels.
Gypsum-fiber roof panels are known in the art for use in low-slope roofing systems. A suitable example of such a panel is USG SECUROCK® Gypsum-Fiber Roof Board, manufactured by United States Gypsum Company, Chicago, Ill. These panels are provided in a variety of thicknesses, ranging from ¼-inch, ⅜-inch, ½-inch and ⅝-inch. The panels are homogeneous (meaning lacking face paper on both front and rear main panels), being made of a slurry of gypsum, reinforcing fibers of wood, carbon, glass, polyester, nylon and other materials, as well as other related additives that is placed and formed on a Fourdrinier machine, then pressed, allowed to set, dried in a kiln and cut to desired panel dimensions.
To enhance strength and handling performance characteristics, the relatively thin ¼-inch SECUROCK panels are formulated with a higher density than the relatively thicker panels. In some applications, when the ¼-inch panels are installed so that adjacent panels abut each other, it has been found that environmental temperature and/or moisture (hygrometric) conditions have caused the panels to expand, so that the joints or seams where adjacent panels abut experience an unwanted “ridging,” where the edges of the panels turn upwards. One suspected factor in this ridging is the relatively greater density of the thinner SECUROCK panels. Conventional SECUROCK panels of greater thicknesses, have not experienced such ridging. It is believed that this is due to the relatively lower densities of these panels, which enable the adjacent panels to crush or compress into each other when subject to environmentally-induced expansion. This ridging phenomenon is considered unsightly, and is detrimental to the performance of the completed roof assembly.
To address the unwanted ridging, one proposed solution has been to install the SECUROCK panels on the roof with small gaps between adjacent panels to accommodate expansion. However, this practice is counter to the practice of trained roofing installers, who habitually abut new panels up against existing panels during installation. This spaced installation also is considered less desirable due to potential panel performance problems in the resulting roofing system.
Accordingly, there is a need for an improved, relatively thin gypsum fiber roof panel that addresses the above-listed problem.